Q&A: Superbug precursor found in US again

July 11, 2016 by Mike Stobbe
This 2006 colorized scanning electron micrograph image made available by the Centers for Disease Control and Prevention shows the O157:H7 strain of the E. coli bacteria. Bacteria with a special type of resistance to antibiotics have been found for a second time in the U.S., increasing worries that the country will soon see a superbug that cannot be treated with known medications. This case, first reported in a medical journal Monday, July 11, 2016, occurred a year earlier in New York. (Janice Carr/CDC via AP)

A New York City patient was infected with bacteria that had a special type of resistance to antibiotics last year, the earliest known case in the U.S. of bacteria that could lead to a superbug impervious to medications.

The bacteria were found in a patient who was treated in May of 2015 and reported in a study published Monday. They were discovered by an Iowa company that's been testing thousands of bacteria collected from patients from around the world over the last two years.

The company, JMI Laboratories, found hundreds globally that were resistant to colistin, an old, powerful antibiotic that is now seen as a drug of last resort. Health officials worry that these bacteria will spread their resistance to last-resort antibiotics to other bacteria that are already resistant to front-line antibiotics, creating germs that can't be killed by any known drugs.

A similar infection was reported in a Pennsylvania woman earlier this year and initially reported as the first known U.S. case. But the New York case happened almost a year before, and scientists now believe these bacteria were likely in people in the U.S. even earlier.

WHY ARE PEOPLE WORRIED?

Since the 1940s, doctors have used antibiotics to beat back a large number of dangerous bacterial diseases. Over the decades, bacteria have adapted to become resistant to more and more of the drugs. An exception has been an old antibiotic called colistin. But recently scientists have spotted evidence of colistin-resistant infections in animals and people in China, Europe and Canada. Now, at least two human infections have also been seen in the United States.

ARE THESE COLISTIN-RESISTANT GERMS SOME NEW BREED OF BACTERIA?

No. In both the U.S. cases, they were E. coli bacteria, a common type of germ found in the gut. In both cases, while they were resistant to colistin, they were vulnerable to more common antibiotics and were not hard to treat. "It's not an immediate threat," said Mariana Castanheira, one of the study's authors.

SO WHAT'S THE PROBLEM?

Bacteria often mingle and swap genetic material. The E. coli bacteria in New York and Pennsylvania were vulnerable to other antibiotics, but some other germs are nearly impervious. Colistin is reserved for germs that already resist one of the other last lines of defense—antibiotics called carbapenems. If carbapenem-resistant bacteria absorb the colistin-resistance gene, that could set the stage for creation of supergerms impervious to all known antibiotics.

WHEN DID THIS FOR OF ANTIBIOTIC RESISTANCE FIRST APPEAR?

Scientists think the colistin-resistant gene was in bacteria in livestock in China as far back as the 1980s. Reports of these bacteria in humans date back to 2008, and since have been confirmed in Asia, Europe, Canada and the United States.

Until this study, none of the reported U.S. infections were thought to have occurred before this year, when colistin resistance was detected in pigs in Illinois and South Carolina, and in the 49-year-old Pennsylvania woman who had gone to a military clinic with symptoms of a urinary tract infection.

But the new report found the New York case in 2015, and Castanheira said it's likely colistin-resistant bacteria were in the United States before that.

WHAT MORE IS KNOWN ABOUT THE CASE?

No additional details about that patient were released by the researchers or in their study, published online Monday in Antimicrobial Agents and Chemotherapy, a journal of the American Society of Microbiology. The authors believe it is the most comprehensive search to date of bacteria that have the colistin-resistant gene, which is known as mcr-1.

Explore further: Second US patient identified with super-resistant bacteria

More information: Journal: aac.asm.org/

Related Stories

Second US patient identified with super-resistant bacteria

June 28, 2016
A second US patient has been infected with a superbug that is highly resistant to last-resort antibiotics, scientists said Monday.

US to establish lab network for combating 'superbugs'

June 1, 2016
US authorities said Tuesday they are establishing a network of labs that can respond quickly to antibiotic-resistant "superbugs," following America's first human case of a dangerous strain of E. coli.

Colistin-resistant gene detected in the US for the second time

July 11, 2016
For the second time, a clinical isolate of a bacterial pathogen has been detected in humans in the United States which carries the colistin resistance gene, mcr-1. This may also be the first case to show up in the US. That ...

First discovery in United States of colistin resistance in a human E. coli infection

May 26, 2016
The Multidrug Resistant Organism Repository and Surveillance Network (MRSN) at the Walter Reed Army Institute of Research (WRAIR) characterized a transferrable gene for colistin resistance in the United States that may herald ...

Resistance to antibiotics and to immune system are interconnected in bacteria

June 30, 2016
Antibiotics and the immune system are the two forces that cope with bacterial infections. Now, two studies from Isabel Gordo's laboratory, at Instituto Gulbenkian de Ciência (IGC, Portugal), show for the first time that ...

Recommended for you

PET scans to optimize tuberculosis meningitis treatments and personalize care, study finds

December 6, 2018
Although relatively rare in the United States, and accounting for fewer than 5 percent of tuberculosis cases worldwide, TB of the brain—or tuberculosis meningitis (TBM)—is often deadly, always hard to treat, and a particular ...

Silicosis is on the rise, but is there a therapeutic target?

December 6, 2018
Researchers from the CNRS, the University of Orléans, and the company Artimmune, in collaboration with Turkish clinicians from Atatürk University, have identified a key mechanism of lung inflammation induced by silica exposure, ...

Infectivity of different HIV-1 strains may depend on which cell receptors they target

December 6, 2018
Distinct HIV-1 strains may differ in the nature of the CCR5 molecules to which they bind, affecting which cells they can infect and their ability to enter cells, according to a study published December 6 in the open-access ...

Protecting cell powerhouse paves way to better treatment of acute kidney injury

December 6, 2018
For the first time, scientists have described the body's natural mechanism for temporarily protecting the powerhouses of kidney cells when injury or disease means they aren't getting enough blood or oxygen.

New study uncovers why Rift Valley fever is catastrophic to developing fetuses

December 5, 2018
Like Zika, infection with Rift Valley fever virus can go unnoticed during pregnancy, all the while doing irreparable—often lethal—harm to the fetus. The results of a new study, led by researchers at the University of ...

Study highlights potential role of bioaerosol sampling to address airborne biological threats

December 5, 2018
As a leading global city with a high population density, Singapore is vulnerable to the introduction of biological threats. Initiating an early emergency response to such threats calls for the rapid identification of the ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.